1. Field of the Invention
The present invention relates, in general, to an antenna unit and a wireless communication apparatus. More particularly, the present invention relates to an antenna unit which is provided in a wireless communication apparatus for performing wireless communication, and in which variations in antenna characteristics depending on surrounding parts are limited, and to a wireless communication apparatus using the antenna unit.
2. Description of Related Art
recent years, information processors such as personal computers and PDAs incorporating wireless LAN functions and standards such as IEEE802.11a/b/g and Bluetooth® have come into wide use. In information processors having wireless LAN functions, it is desirable to realize an antenna such that the influence of internal parts or the like of the information processor on the antenna is reduced and the antenna has stable characteristics.
As a method for limiting the influence of noise or the like from an information processor on an antenna, a method of using, for example, a shielding member of a display panel as a ground circuit for an antenna has been proposed (for instance see Published Unexamined Japanese Patent Application Laid-Open No. 2000-174527).
In certain of the wireless LAN functions, such as EEEE802.11a/b/g and Bluetooth, different frequency bands in accordance with the standards may be used and, therefore, it is often desirable to realize or utilize all the frequency bands by one antenna. In order to achieve this, it is necessary to determine characteristics of the antenna including impedance with higher accuracy at the time of manufacturing and assembly.
However, in a case where one antenna is used in concert with a system utilizing in a plurality of information processor types, the characteristics of the antenna are often changed for a variety of reasons including the position or location of parts and the arrangement of the display panel, each of which may also be dependent on the particular kind of processor used. For example, in one information processor, the characteristics of the antenna may be affected by variations in the position of certain parts and wiring, whereas if another information processor were used, similar effects would not be realized.